The easiest way to import Poliigon imperfection maps into Cinema 4D is by using the Poliigon Cinema 4D Plugin, located here: https://www.poliigon.com/cinema-4d

Once you've imported the map to your scene, you'll notice that the addon imports it as a distinct material, which isn't what we want

Select the texture node, as well as any adjustments nodes present (this might include an invert node, if it's an older Poliigon material that imported as a gloss map instead of roughness) and copy them

Return to the base material you want to add to, and paste the nodes into this material

If importing manually by creating a texture node, depending on the renderer selected (Vray for example), you may have import options allowing you override the gamma correction. For a basecolor/diffuse map, you can leave the setting to automatic, but for roughness or bump maps, you'll want to set it to "override" so that no gamma correction is performed. This process may differ between render engines, so we recommend inspecting the texture node after import to ensure the correct color space or gamma settings are applied

Add a 'Layer RGBA' node

Connect your base material's surface node to the Layer 1 input

Connect your imperfection surface node to the Layer 2 input

Set the blend mode of layer 1 to 'Screen'

Adjust the 'Mix' amount to the desired strength

Add a 'Bump 2D' node and feed in the base material's normal map into the 'normal input' and imperfection map into the 'bump_map' input.

Adjust strength as required via the 'Bump 2d' node.

Add in a 'Layered' node and connect the base material's map to Layer 1, and the surface imperfection map to Layer 2

Change the blend mode of the top layer to either 'Multiply' or 'Screen' based on which map variation you selected (black on white, or white on black)

Adjust opacity of the top layer to get the desired strength

Add a Vray Bump Material upstream from your base material

Connect your base material to the 'Base Material' input

Connect your surface imperfection map to the 'Texture Map' input, and set the map type to 'Bump'

Adjust the multiplier setting to the desired strength

In the import section of this help article, Poliigon recommended copy the nodes from the material created upon importing the surface imperfection asset, to your base material. However in Corona we can use the created material as-is.

Create a 'Layered Material'

Select your base material for the 'Base Material' input

Select your created material containing the imperfection map in one of the additional layer channels

Adjust the 'Amount' setting to the desired strength (in this setup you may want to adjust the strength of the imperfection map in it's own material, before adding to the layered material)

Add in a 'Composite Texture (Legacy)' node and connect the base material's map to Input 1, and the surface imperfection map to Input 2

Change the blend mode of the top layer to either 'Multiply' or 'Screen' based on which map variation you selected (black on white, or white on black)

Adjust opacity of the top layer to get the desired strength

Connect the imperfection map to the 'bump' input of the material, selecting the 'invert' button depending on whether the map you downloaded was black details on white, or white details on black

Add in a 'Color Composite' node and connect the base material's map to the 'Base Color' input, and the imperfection map node to the 'Blend Color' input

Change the blend mode of the top layer to either 'Multiply' or 'Screen' based on which map variation you selected (black on white, or white on black)

Adjust the blend weight to the desired strength

Add a 'Bump Blender' node to your workspace

Connect your material's normal map to one input

Connect your surface imperfection map node to another input

Check the 'Additive' check box and adjust the weight of the imperfection layer to the desired look